pgaspar's solution to RNA Transcription on the Ruby track

Instructions

Test suite

Solution

Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Given a DNA strand, return its RNA complement (per RNA transcription).

Both DNA and RNA strands are a sequence of nucleotides.

The four nucleotides found in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T).

The four nucleotides found in RNA are adenine (A), cytosine (C), guanine (G) and uracil (U).

Given a DNA strand, its transcribed RNA strand is formed by replacing each nucleotide with its complement:

G -> C
C -> G
T -> A
A -> U

For installation and learning resources, refer to the exercism help page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

Run the tests from the exercise directory using the following command:

ruby rna_transcription_test.rb

To include color from the command line:

ruby -r minitest/pride rna_transcription_test.rb

Source

Rosalind http://rosalind.info/problems/rna

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

rna_transcription_test.rb

require 'minitest/autorun'
require_relative 'rna_transcription'

# Common test data version: 1.0.1 cb1fd3a
class RnaTranscriptionTest < Minitest::Test
  def test_rna_complement_of_cytosine_is_guanine
    # skip
    assert_equal 'G', Complement.of_dna('C')
  end

  def test_rna_complement_of_guanine_is_cytosine
    skip
    assert_equal 'C', Complement.of_dna('G')
  end

  def test_rna_complement_of_thymine_is_adenine
    skip
    assert_equal 'A', Complement.of_dna('T')
  end

  def test_rna_complement_of_adenine_is_uracil
    skip
    assert_equal 'U', Complement.of_dna('A')
  end

  def test_rna_complement
    skip
    assert_equal 'UGCACCAGAAUU', Complement.of_dna('ACGTGGTCTTAA')
  end

  def test_correctly_handles_invalid_input_rna_instead_of_dna
    skip
    assert_equal '', Complement.of_dna('U')
  end

  def test_correctly_handles_completely_invalid_dna_input
    skip
    assert_equal '', Complement.of_dna('XXX')
  end

  def test_correctly_handles_partially_invalid_dna_input
    skip
    assert_equal '', Complement.of_dna('ACGTXXXCTTAA')
  end

  # Problems in exercism evolve over time, as we find better ways to ask
  # questions.
  # The version number refers to the version of the problem you solved,
  # not your solution.
  #
  # Define a constant named VERSION inside of the top level BookKeeping
  # module, which may be placed near the end of your file.
  #
  # In your file, it will look like this:
  #
  # module BookKeeping
  #   VERSION = 1 # Where the version number matches the one in the test.
  # end
  #
  # If you are curious, read more about constants on RubyDoc:
  # http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html

  def test_bookkeeping
    skip
    assert_equal 4, BookKeeping::VERSION
  end
end

class Complement
  DNA_KEYS = 'GCTA'.freeze
  RNA_KEYS = 'CGAU'.freeze

  def self.of_dna(dna)
    return '' unless valid_dna?(dna)
    dna.tr(DNA_KEYS, RNA_KEYS)
  end

  def self.valid_dna?(dna)
    (dna.chars - DNA_KEYS.chars).none?
  end
end

module BookKeeping
  VERSION = 4
end

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pgaspar's solution

to RNA Transcription in the Ruby Track